Why fourth GOP debate could be a game-changer for Rubio and Bush

Let’s go back to that new Washington Post/ABC News poll for a closer look at Marco Rubio and Jeb Bush. As we mentioned before, Rubio sits at a 58 percent favorable rating among Republicans. But here's an interesting nugget his campaign is no doubt focusing on today: One in 5 Republicans have absolutely no opinion of Rubio. That’s good news for the young candidate as it signals possible growth in a positive way.

Something else in Rubio's favor: He's overwhelmingly popular among strong conservatives with 75 percent of Republicans and independents who call themselves "very conservative" showing a favorable view of him.

Conversely with Jeb Bush, his unfavorable numbers are high with more than a third of Republicans having an unfavorable opinion of the former Florida governor. -- That's higher than any other candidate tested in the poll.

Tuesday night’s debate could especially be a game changer for Rubio and Bush as we mark 52 weeks away now from Election Day 2016.